Mitama: Nin

Both anime include ninjas(male and female) involved it more or less erotic adventures(rather the latter one as both are hentai animations after all). Mizugi Kanojo focuses more on humoristic aspect of the story while Mitama : Nin on variety of sex scenes and something what we can call a story(keeping in mind that usually these kidn of productions have not very sophisticated content). The last information worth of mentioning is that Mitama : Nin includes more yuri scenes.